The aim of the present invention is to enable a tire building machine to be fed fully automatically with a succession of continuously extruded tread portions of predetermined length. A further aim of the present invention is to enable a tread portion to be fed to a tire building machine without inducing unwanted stress or distortion in the tread portion itself. A further aim of the present invention is to enable a tread portion to be transferred from an extruder, whereby the tread is produced continuously, to a tire building machine in such a manner as to preserve as much of the original extrusion heat as possible inside the tread portion.